Internal combustion engines and pistons therefor



1959 w. l. GOLDSMITH 2,911,963

INTERNAL COMBUSTION ENGINES AND PISTONS THEREFOR Filed Oct. 23, 1958 Fla].

lNv ENIOR WALTER I. GOLDSMITH AT TQQNEY United States Patent INTERNAL COMBUSTION ENGINES AND PISTONS THEREFOR Walter Iorwerth Goldsmith, Hove, England, assignor to Ricardo & Co. Engineers (1927) Limited, London, England, a British company Application October 23, 1958, Serial No. 769,117

Claims priority, application Great Britain November 7, 1957 2 Claims. (Cl. 123-4139) This invention relates to reciprocating internal combustion engines and pistons therefor of the kind in which the piston or each piston includes within it a trough, which may be constituted solely by an internal formation with in the piston body or partly or wholly by a separate insert, the open side of such trough facing the piston crown and the arrangement being such that during operation a quantity of oil is retained and shaken back and forth between the trough .and the piston crown to cool the latter, the oil being renewed at an appropriate rate by delivery of oil into the trough and consequent escape of oil at a similar rate out of the trough towards the end of each outstroke of the piston over an appropriate part or parts of its edge, or through one or more outlet passages having their upper ends at a suitable level above the base of the trough.

Examples of pistons of the kind referred to are described and illustrated in the present applicants United States of America Patent No. 2,523,699 and United States of America Patent No. 2,815,011.

An object of the invention is to enable pistons of the kind in question to be employed more readily in internal combustion engines where it is not convenient or readily possible to provide an appropriate oil passage in the con necting rod for delivery of oil into the trough.

According to one aspect of the invention an internal combustion engine comprises in combination a working cylinder with a working piston arranged to reciprocate therein, the piston being formed or provided in its interior with parts constituting an oil-retaining trough the open side of which faces the piston crown, such trough being formed with an edge portion or one or more outlet pas sages arranged to determine approximately the maximum depth of oil which it can contain at the end of its outstroke and means rigid with the cylinder for delivering oil into the trough during the part of the piston movement adjacent to the end of its outstroke.

The arrangement for delivering oil into the trough may vary but in one convenient arrangement the piston assembly includes a cup-like part having its open side facing the piston crown and so arranged that it will receive oil from the oil delivery means during the part of the piston travel adjacent to the end of its outstroke and so formed and arranged that this oil will be transferred by momentum from the cup-like part into the body of the trough towards the end of the instroke of the piston. Thus in such an arrangement the base of the cup-like part conveniently lies substantially below the base of the trough while an appropriate deflecting or guide surface is provided above the cup-like part by which the oil thrown from the cup-like part towards the piston crown will be deflected into the body of the trough.

Thus in such an arrangement there may be formed in the piston wall adjacent to the open mouth of the cup like part a passage which, towards the end of the outstroke of the piston, communicates with a fixed oil 2,911,963 Patented Nov. 10, 1959 delivery passage in the cylinder wall to receive and lead oil from the said passage into the cup-like part.

According to another aspect of the invention the in vention comprises a piston of the kind referred to formed or provided in its interior with parts constituting an oil-retaining trough, and a cup-like part constructed and arranged and operating as above described, for use with a cylinder having appropriate means by which oil can be delivered into the cup-like part during operation.

In pistons or internal combustion engines embodying pistons according to the invention the trough and/or the cup-ike part when provided, may be formed partly or wholly as a unit with the piston body or partly or wholly as a separate unit or separate units secured within the piston body and one construction of the latter type according to the invention is illustrated by way of example in the accompanying drawings, in which:

Figure l is a sectional side elevation of a piston and its associated cylinder, the section being taken in a plane containing the piston axis.

Figure 2 is a cross-section of the piston, the crosssection being taken partly in each of two planes as indicated by the line IIII in Figure l, and

Figure 3 is a side elevation of the unit incorporating a cup-like part and constituting the trough as incorporated in the piston shown in Figures 1 and 2.

In the construction shown it may be assumed that the engine comprises a cylinder block 1 in which are formed a number of cylinders in line in well known manner of which one is shown at 2 in Figure 1. Each cylinder is provided, as shown in Figure 1, adjacent to its inner end with an oil delivery passage 3 passing through the cylinder wall and communicating with a supply gallery 4 in which oil is maintained under pressure by the normal lubricating oil pump of the engine. In the arrangement shown it will be seen that the delivery passage 3 is inolined somewhat towards the upper end of the cylinder but it may be otherwise arranged.

Arranged to reciprocate within the cylinder, as by being connected to a crankshaft in known manner by a connecting rod indicated at 5, is a piston comprising a body part consisting of a crown 6 from which extends an externally cylindrical ring-carrying part 7 merging into a skirt portion 8 in known general manner, the skirt portion being formed also in known manner to provide gudgeon pin bosses to receive the gudgeon pin indicated at 9 by which the piston is connected to the connecting rod 5.

As shown, the underside of the piston crown 6 is formed with a generally concave recess 10 and with three bored and drilled bosses 11 projecting from the base of this recess and providing downwardly-facing abutment faces. These bosses, of which only two appear in Figure 1, are arranged to receive bolts 12 from the positions of which in Figure 2 the positions of the three bosses in the plan view of the piston can be seen.

Arranged within the piston body 6, 7, 8 is a separate trough member consisting of a part 13 constituting the body of the trough and lying opposite to the concave recess 10, this body part being formed with a rim 14 extending towards the underside of the crown of the piston bu-t spaced therefrom and with drilled bosses 15 in such rim through which pass the bolts 12 by which the trough is thus clamped to the bosses 11.

Formed on and depending downwards from one side of the body 13 of the trough member adjacent to the oil delivery passage 3 is a cup-like part 16 the side walls of which are extended upwards above the cup proper as shown at 17 to a point approximately level with the upper edge of the rim 14. The under-side of the piston crown above the cup-like part 16, 17 is formed as a curved deflecting surface 18 such that any oil which may 3 be'thrown upwards against this surface out ofthe cup 16 will be deflected over-the rim 14 into the body of the trough 13.

Formed through the wall of the piston skirt "8 slightly above the upper edge of the'cup16 is a transfer passage 19 the inner end of which'lies above the cup 16- while its outer end communicates with a vertical groove 20 in the outer surface of the skirt *8 of the piston. The groove 20in turn communicates with the oil delivery passage 3, at least over the end part of the outstroke of the piston.

Thus, during the end part of each outstroke of the pistonoil is delivered from the passage 4 through the passage 3 into the groove 29 and from this groove through the transfer passage-19 into the cup 16 in which it is caught. Such oil, towards the end-of the subsequent instroke of the piston is thrown by'reason of its moment'ur'n upwards out of thecup 1-6 and against the surface 18 by which it is deflected over the rim 14 into the body of the trough 13. Towards the end of each outstroke of the piston moreover, under stable conditions, an'equivalent quantity of oil will escape over the rim 14 into the interior of the piston and thence into the engine crank case so that, while a quantity of oil is shakenup and down between the body of the trough 13 and the piston crown during operation of the engine, this oil will be replenished continuously at a rate depending upon the quantity of oil delivered into the cup-like part 16 during replenishment and/or the meanquantity of oilshaken back and forth can be varied to suit requirements.

Moreover, although in the arrangement shown the quantity of oil retained in the body of the trough at the end of each outstroke'of the piston is determined by the height of the edge of the rim 14 above the base of the trough, otherforms of trough having one or more outlet passages arranged to determine approximately the maximum depth of oil which the trough can contain at the'end of each outstroke may be employed, for example as generally described in the specifications of one or other of the present applicants United States of America Patent No. 2,523,699 and United States of America Patent No. 2,815,011.

What I claim as'my invention and desire to secure by Letters Patent is:

1. A piston for an internal combustion engine including in combination a crown portion, a ring carrying portion rigid with the crown portion and a skirt portion rigid with the ring-carrying portion, an oil retaining trough within the piston, the open side of which trough faces the piston crown, such trough being formed to contain a predetermined maximum depth of oil at the end of the piston outstroke, a cup-like part carried by the piston with its open side facing the piston crown and guide means above said cup-like part for directing into the trough oil thrown upwards from the cup-like part.

2. A piston as claimed in claim 1 in which the said guide means comprises a surface on the piston by which oil thrown from the cup-like part is deflected laterally into the trough.

Winton July 31, 1923 Holt et a1. Sept. 26, 1950 

